Data represents information that has useful value. Data can take the form of stored information. Data storage can be in analog form. Data storage can also be in digital form.
Data in digital format may be communicated between two nodes. At a receiver in a digital communication system, a digitally-encoded data stream may be received as an analog signal and converted to a digital format by an analog-to-digital converter (ADC). The ADC interprets the data stream as a function of time. For example, some ADCs may be synchronized to a clock signal that determines when a voltage signal is to be sampled. Accurate recovery of a stream of digital data, for example, may depend on accurate clock timing. In some implementations, timing of a clock signal may determine whether a symbol in a data stream is interpreted, for example, as a one or as a zero. Sometimes, a clock signal is received, but its phase information may be uncertain. To enhance data accuracy and data integrity, various clock signal phase alignment operations may sometimes be performed before launching data or upon receiving data so that accurate clock phase information may be supplied to the ADC.
In integrated circuit applications, ADCs may typically perform critical timing functions using one or more circuit stages that are implemented with transistors. In various ADC circuits, some of the transistors may operate in a linear mode to process analog signals. In some ADC circuits, certain transistors may be designed to operate as ideal switches (e.g., digital signals). An ideal transistor switch may operate in either an on state or an off state in response to a control signal. In practice, however, transistors in real integrated circuits may exhibit non-ideal behavior related to intrinsic device properties and/or extrinsic parameters such as, for example, device process parameters, applied voltage, and device temperature.